Hydroponic culture is widely known as a method used for growing plants without soil, in which the plant roots are brought into contact with water containing dissolved nutrients. Small particles of a chemically inert material, such as, for example, expanded perlite or expanded clay, are generally provided in a net pot to support the roots. These particles provide a suitable growing environment for the plant roots and the net pot allows the water to adequately contact the roots.
Different methods exist to supply nutrient containing water to the roots of the plants.
A first method (generally referred to as NFT "Nutrient Film Technique") consists in the periodical flooding of the container with the nutrient containing water. This water is maintained in the container for a predetermined period and is then drained from the container.
A second method consists of continuously supplying minute quantity of the nutrient containing water to the roots. This can be done by allowing the water to drip continuously onto the particulate material or by providing a continuous small stream of water in contact with the particulate material.
A third method (generally referred to as aeroponic culture) consists in periodically spraying nutrient containing water onto the roots to keep them moist. In this method, humidified air provides the environment in which the plant roots grow.
While many types of containers may be used for the different classes of hydroponic culture generally defined hereinabove, it has been found that available containers usually suffer many drawbacks. For example, they may be difficult to clean between uses, may be designed for a single class of hydroponic culture and/or designed for a predetermined size of net pot.